Chipping away

The summer is the season when West Sussex County Council – and presumably many other British councils – decide to start spreading gravel on their country lanes, sticking it down with tar and hoping that motor vehicles will ‘bed it in’. IMG_4553This technique is apparently called ‘chip seal’.

It is simply awful to ride on, especially when it has just been laid – the gravel is still loose, and slippery to ride on. Stones get flung up, particularly by passing vehicles, which rarely stick to the 20mph suggested limit. And it’s a poor surface to ride on, even when it has been ‘bedded in’ – rough, and noisy, and far worse than a machine-laid tarmac surface.

Worse than that, chip seal appears – to me at least – to actually accelerate the deterioration of a road. Here’s an example, a mile away from where the new chip seal has been laid in the photograph above.

IMG_4555 IMG_4554This road was ‘chip sealed’ in the last four to five years (I can’t remember precisely when). But as you can see, the layer of gravel has been intermittently blasted off, leaving a bumpy patchwork surface, partly composed of the remaining chipseal, and the underlying original road surface. Again, absolutely awful to ride on, but more problematically, the kind of road surface that is going to deteriorate very rapidly. Potholes are already starting to develop in the areas where the chipseal has been blasted off. The depressions are places where water is retained, perfect for the development of road damage.

I’ve cycled on country lanes in most of the countries of western Europe, including places where roads are subject to extremes of temperature – Switzerland and Sweden. Yet no other western European country appears to employ ‘chip seal’ – they seal roads properly, with machine laid surfaces. My guess is that these roads – while more expensive to lay in the short term – are much cheaper in the long term, because they last much longer than this strange ‘gravel’ approach.

Why does Britain do things differently? Is chip seal genuinely cost-effective? Answers please!

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34 Responses to Chipping away

  1. I really don’t think Highway Engineers weigh up the long term costs against the immediate costs, as the old adage goes “If a jobs worth doing it’s worth doing well”. Why repeat the same ineffective method every 4-5 years when you could do it right first time and not worry about it again for decades? (pure guesswork on that time frame)

    We had a similar problem spot in Croydon on a bus lane with one particular pot hole, it was always filled with substandard filler and invariably during the next cold snap would just end up with a massive pothole again. Of course the “fun” with this being a dedicated bus lane that the buses themselves had basically made 2 tracks down the lane with the central hump being a black sooty mess as it was where the exhaust pipes came out and so in trying to avoid that you’d be on a collision course for the pothole which has claimed at least 1 inner tube for me.

    • Paulc says:

      I’m pretty sure the highway engineers themselves would like to do things properly, but it’s the “bean counters” who are in charge…

    • Jan says:

      Can you shed some light on how these decisions are made? In the Netherlands, in most cases a road construction company would get a contract for a new road or complete overhaul, including 10 or 20 years of maintenance. Add some fines for every day of road closure (more during peak hours, less for scheduled maintenance in weekends, etc.), and they’re free to calculate the optimal solutions themselves.

  2. parimalkumar says:

    Surface dressing / chipping like this is absolutely awful and it’s not just country lanes that local authorities do this on. Surrey County Council did this on a main road that connects Walton on Thames to Hampton Court. On flat roads, the chips build up exactly where the secondary position is, effectively reducing the width of the road and further infuriating drivers who could overtake cyclists before, but suddenly can’t because the rider is riding closer to primary more often. When the country lane turns up, it actually makes descending much harder and more treacherous than going up the climb (and that’s coming from a fat bloke on a bike). I am working on my local councillors to ensure that surface dressing / tar & chip is never used on roads near me.

  3. geoffrone says:

    They did it in Burgess Hill, I especially recall the surface laid on Cants Lane about 6 years ago, and had to do it properly a year later. I thought that W Sussex had learned their lesson. I agree, it is an atrocious method and not only for cyclists.

  4. Matthew.W says:

    It is a bugbear of mine as well.

    It can work when cars are driven in a straight line at a constant speed. On roads such as these, the chips bed in well and in an approx. “Franklin secondary” position you get a nice smooth surface to ride along.

    Any acceleration, braking & turning, especially around junctions, vehicles just rip the chips off and lead to the problems you’ve highlighted.

    Would it really add to the cost of the resurfacing to send a heavy road roller along afterwards?

  5. Mark says:

    WSCC seem to love surface dressing, it lets them ignore the road for another few years. Their contractors never sweep up the loose stones either. It is not a substitute for proper pothole repairs, yet WSCC use it as one!

    On two roads in Horsham I regularly cycled on, the surface dressing lasted less than 1 year before it disintegrated, restoring the road to the pothole-ridden mess that it was before. Some of the potholes ended being several meters long – they were so big they even had potholes inside them. It took WSCC over 2 years before they finally resurfaced those roads correctly and I damaged a wheel in that time.

  6. Yep, can’t stand it, they do it periodically round here and all the side roads end up with dunes of gravel.

  7. velovoiceblogspot says:

    Central Bedfordshire Council are doing this on the very busy road that connects the A5 to Luton via Caddington (the village where I live). It is simply awful! I don’t care how little it costs (and I doubt it was “cheap”), how can anyone think this is a good idea on any aspect you care to assess?

    Sounds like Sally is having the same problem too:
    and that, while taking the time and energy to complain *may* eventually bear fruit, the fruit is half rotten:


  8. Paul Smith says:

    Yup, Rusper Road for about 3 miles and Forest Road, urgh getting fewer escape routes out of town!

  9. meadowend says:

    BucksCC has just done it on the A40 between Beaconsfield and Holtspur. That’s after having spent every night for nearly two weeks doing the A40 in Beaconsfield Old Town properly. Bizarre, and very bad news for cyclists.

    • meadowend says:

      Further to my previous comment, BucksCC has actually swept the road section I mentioned, removing all of the loose chips before repainting the signage. It’s now a lovely surface to cycle on. We’ll see whether it lasts the winter…

  10. Why do they do it? It’s cheap and makes it look as though something is being done. In reality, as you have already pointed out, it is an unsuitable short term measure leading to a poorer surface in a very short space of time. In Gloucestershire they have deemed it suitable for the Main A road linking Gloucester to Bristol

  11. Yes, even when done ‘well’ it’s pretty awful in the short term, poor to ride on in the medium term and, as your pictures show, then quickly fails -with the eroded gravel worsening the condition of the ‘proper’ surface underneath.
    The problems really come when it is done badly:
    1) In Horsham WSCC use it without filling the cracks and potholes first; it has no useful purpose here as the defects remain, they are just harder to spot as you ride along.
    2) North Parade had this surface laid in the main running lanes (which were in excellent condition), but not at the junctions or along the cycle lanes (which, inevitably, were not in quite such good condition). It was so poorly laid that the cycle lanes filled with gravel for months and months, the main lanes wore bare and the whole thing had to be redone. It has lasted somewhat better this time, but is still going bald again. No one has yet got around to resurfacing the cycle lanes or junctions which were most in need of it and have suffered accelerated wear from all that loose gravel.
    3) Cars are routinely allowed onto the road immediately after it has been laid -hence the bare stripe at the end of our road where the very first vehicle spun its wheels in the liquid tar as it accelerated onto the new surface.

  12. They’ve done it recently down here on a road that was absolutely fine beforehand. Went on it not long after they did it then avoided it for a few weeks. It’s not too bad now, but nowhere near as good as a proper road, plus there’s the risk of getting hit by stones whenever you are overtaken.

  13. alstorer says:

    Put simply it should be outlawed.

  14. One highway authority plz says:

    I cycle all over London, and I am saddened to say that the whole road surface is like a really bad hard porridge jigsaw. How can one of the richest cities in the world have such crap roads?

    The City of London is the worst! It makes me laugh in horror every time I make the mistake of cycling from Bank to Aldgate. With trillions of pounds invested in that area, how come their roads are worse than in Karnataka in India, which takes the prize for poor Indian roads. Most road surfaces in India are infinitely superior to what we have to suffer on our daily commute in London.

    There is not one metre of road that has not been torn up or patched, and none of it is the same quality in London. There is almost no smooth tarmac – apart from a couple of hundred yards between Forest Gate police station and the Princess Alice pub. How did that get there? It’s lovely. Perhaps we should have cyclists’ conventions to come and ride it, to experience the joy of judder-free cycling.

    Even the brand new segregated cycle “superhighway” from Stratford to Bow is lumpy, bumpy and often waterlogged, and unpleasant to ride on, if you have pumped up your tyres properly. How did they manage to do that, on a new stretch of flagship cycle path?

    I was thinking of doing some research into “Why are London’s roads so badly surfaced?”. If anyone else has taken the trouble to do this to save me the trouble, please let us all know.

  15. plien says:

    It took me a while to find out what you meant. I have seen this on back roads in the country. Those roads are tipically just one level above dirt roads & paths. Apperantly the Dutch term for it is split. Doesn’t that sound lovely.
    It’s cheap, it is supposed to be good for adding skid resistance. One doesn’t need it as a cyclist & it only harms. Can’t say i’ve seen it used on cycle paths.

    Here is a short article about it, with a link to a pdf from fietsberaad, both in Dutch i’m afraid;

  16. Matt says:

    I never thought I’d find myself defending surface dressing. I’m not a fan but it is effective from a technical, operational and financial perspective as a road maintenance technique. As with any road maintenance it needs to be done properly to be that effective and most of it is. 1000s of km of road will be surface dressed in the Uk this year. It effectively seals the road from water ingress (greatly increasing the road life), restores skidding resistance. It is horrible to cycle on newly laid and has a deep texture even once bedded in so is never a great ride. It’s much rarer in urban areas so if you don’t like it move to the city!

    • I don’t see how a surface that ends up with bald stripes from wheel wear after only a year or two is ‘greatly increasing’ road life. It may well be that this only happens where the surface is not laid properly; in that case poor laying is a real issue that needs to be addressed.
      I have been told before that the surface dressing is done to restore skid resistance but that does not explain to me why it is done on relatively low speed 30mph urban roads, leaving the junctions (where I would have thought skid resistance degrades faster and is more important) untreated. Cyclists also experience significantly worse skid resistance for quite prolonged periods as they often end up riding in the gravel that builds up along the edge of the road.
      I can see that the benefits might outweigh the disadvantages on a lightly trafficked rural road where the surface lasts long enough to reduce frost and water damage for a few winters, but I suspect that the technique is being over-used.

      • Matt says:

        Yes – if it is stripping off within 24 months it has been badly laid. Who cares about cycle skid resistance? There is no measure of this that I’m aware of and no criteria for it so it is impossible to design for. The skidding resistance of a few hundred cyclists versus 10s of thousands of motorists means this is unlikely to be a factor in any maintenance engineer’s assessment. Skidding resistance is still a factor on low speed (30mph) roads although prolonging life is probably the main criteria here. I doubt the technique is being over used in terms of extending the average highway authority’s maintenance budget. However it will be interesting to see if it maintains it’s position in the maintenance armoury as more sophisticated asset management models start to become more prevalent.

    • Jitensha Oni says:

      Yes, and drive a car or use public transport too presumably.

      However, the reasons for it being effective that you give can’t be the whole story or we’d have surface dressed roads everywhere in the countryside. Miles Lane in Cobham, Surrey was done in this fashion a short while ago (and yes any corners are now horribly rutted), yet the adjacent Fairmile Lane was done about the same time in beautiful smooth new tarmac. A lay person like me could see no reason for the difference based on pre-treatment surfaces or socio-economic group of residents (or indeed why there was need at all when there were some much worse and busier roads that still haven’t been fixed). There must be a decision matrix of some sort, presumably starting with “is the road in the city?” answer = yes – process = don’t surface dress. I’d like to know what it is in full, or at least where to find it, and I think that was the point of the blog article. Especially since this road was surface dressed last year when it still looked like this – why?,-0.345984&spn=0.019346,0.016351&t=m&z=15&layer=c&cbll=51.364754,-0.354257&panoid=5UsEmMFTlMwfxUyXq3SJ6A&cbp=12,32.28,,0,22.96

      One thing I hate more than surface dressing, is an unexplained apparent waste of money.

  17. D. says:

    Surface dressing like this isn’t even any good for cars. I remember when Bristol City Council decided to surface dress roads within the city, and my car (at the time) was covered in chips where gravel was spat up and knocked paint off, and I had to take it to a garage as the gravel got stuck inside the brakes. Horrible stuff.

    Bristol uses surface dressing for the lower rent areas, whilst the “better” parts of the city get genuine tarmac.

  18. A chipsealed surface like this caused my dad’s motorbike to skid and crash, writing off the bike and very nearly causing serious injury. This cheap half a job solution just causes more problems for vulnerable road users and seems like a waste of money compared to doing it properly in the first place!

  19. D. says:

    Its a bit off topic, mind you, but Bristol City Council recently closed the Pill Path (along the side of the river Avon) for “essential maintenance” prior to Bristol’s Biggest Bike Ride (google it).

    The Path is completely unsurfaced – just a mud track used by joggers, dog walkers, and cyclists – and it had got pretty badly potholed and rutted in places. So, after BBBR I thought I’d go along there to see what wonders the council had done (I’d expected them to level it all off, or something).

    I hadn’t expected them to just fill all the ruts and holes with loose gravel of varying sizes. My old hybrid has Continental Touring tyres on it, and it really doesn’t get on with the gravel. I haven’t been down there since (nearly coming off, and the terror of going over the side and into the river, has put me off going along there again… I’ll just wait until the gravel has washed away or sunk into the mud).

    • Antony says:

      D, I suspect those improvements are the result of the Council using their in-house contractors for the job. Not only do these people not own a plate compactor, they seem to have never laid eyes on a bicycle, much less ridden one on a loose surface. Some repairs they did to the mountain bike trail in Ashton Court a few years ago were similarly slapdash, and were hard to ride even on mountain bikes.

  20. Andy R says:

    Excellent website – even for the pros – explaining the various types of highway and footway surfacing, when and where they should be used, and the associated laying techniques.

  21. tassiedi says:

    Here in Australia, the practice is very common. I checked with my father who is a recently retired roads engineer, and this was his response:

    “This is widely used in Australia and in NZ as it is substantially cheaper than an an asphalt wearing course.
    I cannot quote figures for the two methods, but there would be many kilometres less in dust free surfaces if only asphalt was used.
    Sealing is a process that does require a certain amount of skill in designing the rate of spray of the bituminous binder as appropriate for the amount of traffic and rate of application of the sealing aggregate.
    Sorry about the difficulty of riding on the loose aggregate, but it should clear very quickly”.

  22. pshore2 says:

    This was done so badly one time in Cambridgeshire. After riding a section of very loose ‘chip seal’ on my motorcycle, I got back to tarmac to find very little grip on my tyres on the first corner I came to. I stopped to find the tyres covered in stones that were glued on with tar, and really difficult to remove. Stone on tarmac does not grip, luckily not lethal for me.

    Outlaw it.

  23. Brum Cyclist says:

    It’s used on city streets in Birmingham, with exactly the same results as described above. It’s even being used on new “walking and cycling” routes being built with LSTF and Cycling Ambition Fund money. It results in iffy handling until the unbonded gravel has been redistributed over the surrounding land, a harsh, energy-sapping ride, and punctures. To build these paths they lay a new bitmac path, and then wreck it by covering it with loosely bonded gravel. The council ran out of money trying to make one such path usable, but that didn’t deter them from building further paths using the wretched technique.

  24. Andy says:

    If the pitiful state of UK cycling infrastructure, as compared to the Dutch, is clearly down to 40 years of under/lack of investment, why should highway maintenance, after 40 years of budget cuts, be any different? It has, notoriously, always been the first in line when councils needed to save money. Strangely, until these last three or four bad winters there has been a distinct lack of public protest. Is chip-seal cost effective? Well right now, for most Authorities, it’ll be the only alternative, other than to completely suspend maintenance on certain less used roads.

  25. awavey says:

    as with most things Id guess each council responsible for it has a different set of decision matrices as Ive seen it used just as often in rural and urban locations and there doesnt seem to be a set rhyme or reason to it, it feels more like a decision based upon that years budget and how many roads need fixing.

    but I came across one road recently on a ride, in the midst of them doing the chipping,they were dumping at least 3 times the amount of stone chippings that would normally cover the road surface, with the obvious expectation a good chunk of that ends up lining the hedges or embedded in tyres, or gets picked up by vehicles and deposited elsewhere, but it was like cycling through a thick gravel driveway, I couldnt get much above half my normal speed on that road as a result, and my bike, wheels and kit were then covered in tar deposits and chippings sticking to it (and also had to fend off the occasional chipping stones flung up by passing traffic). they certainly didnt have a roller, and there was no sweeping being done either, it was just basically a truck that sprayed water to damp down the dust immediately following the tar/chipping machine.

    so I left that route well alone for a few weeks as one of my friends did come off their bike due to excess chippings left on a junction entry once and ended up with serious gravel rash as a result and only went back to see what it was like the other day, whilst the majority of the extra chippings have gone the gulleys are basically full of the lose chippings still, so you ride that bit further over,which doesnt please following traffic much.but the surface itself is incredibly rough still and creates alot of rolling friction, which makes its quite energy sapping trying to ride over it,and in lots of place its already worn back to the old surface, though best of all they left all the defects in the road, so you still get all the bumps that were there, they are just now covered in tar and chippings, no doubt to seal them from turning into potholes.

    now fair enough the previous surface was no picnic to ride on (aforementioned bumps) the top surface tarmac had worn through in places, so it needed to be fixed somehow, whether chippings was the answer to that though, I doubt, as its made a road that used to be a reasonably good run into a bit of mess for cycling

  26. James says:

    Ah good ol’ Forest Road. Absolutely horrible to cycle down. They’ve surfaced the 2 bends where you’ve taken your pictures properly which are a joy to ride on, shame they only last for around 50-100 yards. They’ve even filled in the potholes, how long that lasts is anyones guess.

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